1. Filed of the Invention
The present invention relates to a driving system for vehicles which employ an internal combustion engine as a source of driving force, and more particularly to a driving system for vehicles which are designed such that the engine automatically stop idling while they are brought to a stop or hybrid vehicles in which another power source is used to run them with the internal combustion engine being brought to a stop.
2. Description of the Related Art
Vehicles attracting people's attention in recent years are hybrid vehicles and automatic engine idling stop vehicles. The hybrid vehicles are run by a motor using regenerative power and power generated while an engine is driven with the engine being brought to a halt in low-load driving conditions or while the vehicles stops. The automatic engine idling stop vehicles are designed such that the engine automatically stops idling when the vehicles stop.
Some of these hybrid and automatic engine idling stop vehicles are equipped with an auxiliary motor, for example, which is exclusively used for driving an auxiliary unit such as an air conditioner compressor even when the engine stops (for example, refer to Patent Literature No. 1).
In addition, in other hybrid and automatic engine idling stop vehicles, a motor designed to function as a starter is linked to the engine and the auxiliary unit with a clutch provided on the crankshaft, whereby a torque transmission between the motor and the engine is cut off. The auxiliary unit can be driven by the motor (Referring to JP 2000-120463, for example). Here, some of the motors are provided with a planetary gear mechanism and a one-way clutch which are combined to switch reduced speed ratios so as to deal with the rotational speed characteristics relative to the crankshaft of the motor as the starter and the rotational speed characteristics of the motor as a generator. (Referring to Japanese Patents letters No. 3180506 and No. 2758642 for example).
[Patent Literature No. 1]
Japanese Patent No. 3180506
[Patent Literature No. 2]
JP-A-2000-120463
[Patent Literature No. 3]
Japanese Patent No. 2758642
[Patent Literature No. 4]
JP-B-35-14402
However, mounting the auxiliary motor only for driving the auxiliary unit such as the air conditioner compressor causes a problem that the number of components is increased, to thereby increase the production costs. In addition, in the case where the motor functioning as the starter is used to drive the auxiliary unit, providing the clutch on the crankshaft of the engine results in an increase in the longitudinal dimension of the engine along the crankshaft. This causes a big problem in a case where a space for installing the engine is limited.
Furthermore, in a case where the driving system including the motor and the planetary gear mechanism is disposed substantially in parallel with the crankshaft, there is a problem that the engine installation space is largely limited due to the layout of intake and exhaust manifolds of the engine.